Ether in the 19th century

The distant stars bathe in the same lake

Knowledge of the universe in the 19th century was still very limited. We didn't know about galaxies. We imagined all the fixed stars as well as the Sun which is our star. Since the Earth is not the center of the Universe, the reference frame of the ether has been associated with that of the fixed stars, the frame of reference of the universe.

With our current knowledge it was obvious that this could not work. The vast majority of physicists initially condemned Einstein's hypothesis of eliminating the ether. General relativity in 1915 impressed them and its validation by experiments made them doubt. While Albert Einstein was restoring the ether in 1920, one physicist after another was cautiously moving away from it.

The ether proposed by Einstein was too incomprehensible, Einstein himself did not try to advertise it too much.